Regulator



D. w. E\XNER June 18, 1940.

REGULATOR Filed NOV. 26, 1938 INVENTOR Dana/a h/Exner. M Z

ATTORNEY WITNESSES:

Patented June 18, 1940 UNITED- STATES PATENT OFFICE REGULATOR Pennsylvania Application November 26, 1938, Serial No. 242,549

5 Claims.

My invention relates to regulator systems and more particularly to such systems employing regulators of the continuously vibrating type.

In certain industrial applications employing regulators of this type, voltage transients are developed which disturb the desired operation of certain electrical apparatus having circuits adjacent thereto, This may be the case with vibrating regulators used to control the voltage output oi motor generator sets used on railway cars on V locomotives equipped with automatic cab signal equipments which receive their power from such a generator. Tests have shown that under certain conditions of operation transient voltages caused by such vibrating regulators tend to shock-excite the various tuned circuits in the cab signal system and to thus interfere with the proper operation thereof.

An object of my invention is the provision of a vibrating regulator employing means for eliminating undesired transient voltages or so modifying them that they cannot interfere with the said circuits.

Other objects and advantages of my invention will appear from a description of a preferred embodiment of my invention when taken together with the accompanying drawing in which:

Figure 1 is a view, partly in section and partly in side elevation, of a regulator relay that may be employed for controlling the output voltage of an electric generator.

Fig. 2 is a diagrammatic view of a conventional regulator system employing the type of regulating relay illustrated in Fig. 1, and

Fig. 3 is a diagrammatic view of a regulator system organized in accordance with my invention.

Referring to Figure 1, the regulator there illustrated may correspond to that constituting the subject matter of United States Patent No. 1,820,- 712 for Voltage regulator, issued August 25, 1931, to Walter Schaelchlin, and assigned to the same assignee as this application. The regulator comprises a magnetic structure including a central or winding leg I and an outer leg 2 terminating in an annular portion 3 surrounding one end of the winding leg I. A winding 4 is provided for magnetizing the core and is mounted about the major portion of the winding leg I, and connected in series circuit relation with a smaller coil 5 that is mounted upon a movable bifurcated arm 6. The winding 5 is positioned with its conductors surrounding one end of the winding leg I of the magnetic structure and within the flux path between the winding leg and the annular portion 3 of the outer leg 2 that surrounds the left end of the winding leg I as viewed in Fig. 1.

The annular portion 3 of the magnetic structure is provided with upwardly extending bracket portions 1, one of which is shown in dotted lines in Fig, 1, upon which the bifurcated arm 6 is supported by means of a square bar 8 extending through the vanes of the arm 6 between the two bracket portions 1. A similar bar 9 extends between the vanes of the arm 6 to provide a fulcrurn point about which a force is applied to bias the arm 6 against the magnetic pull of the armature winding 5. The bars 8 and 9 are held in their illustrated positions by means of clamping members 12 and I3 that are held together by a bolt H.

The movable coil is mounted upon a metal sleeve I5 that is attached to the vanes of the arm 6 by any suitable means such as rivets l6. The vanes of the arm 6 are connected at their upper ends by means of a transverse member IT to which a bracket I8 is attached for carrying the contact member l9 which may be fastened thereto by means of a screw 22. Two stationary contact members 23 and 24 that cooperate with the movable contact 22 are provided and mounted on the panclboard 30 by suitable means such as brackets 25 and 26, respectively, and screws 21 and 28.

A biasing spring 32 is provided, one end of which is attached, by means of an adjusting screw 33, to a bracket 34 extending upwardly from the magnetic structure, and the other end of which is attached to a fiat hook member 35 which engages the bar 9 to actuate the arm 6 in a clockwise direction as viewed in Fig. 1, thereby normally maintaining the contact members [9 and 24 inengagement.

It will be noted that the positions of the bars 9 and 8 are such that the corner 36 of the bar 8, which forms the fulcrum point about which the arm '6 moves, is below and to the right of the corner 31 of the bar 9 that is engaged by the hook member 35 actuated by the spring 32. A pin 38 may be attached to the arm 32 for limiting the movement thereof.

Referring to Fig. 2 of the drawing, a generator M is provided having an armature winding 42 connected to the circuit conductors 43 and 44, and a field winding 45 that is connected in series with a field controlling resistor 46 between conductors 43 and 44.

The movable contact member IQ of the regulator is connected to a junction point 41 between 2 aaoasoo the field winding 55 and the resistor G6. The I the contact members and it to limit the peat.

stationary contact member 2 3 is connected by conductor 88 to circuit conductor (16 and the stationary contact member 23 is connected through resistortd to circuit conductor The regulator windings t and are connected in series with the resistor 53 and conductors 5i and 52 to be energized in accordance with the voltage appearing between the circuit conductors A3 and 44.

The operation of the regulator is as follows: When the generator 48 is started and the voltage is below its normal or desired value, the contact member i9 is biased by the spring 32 into engagement with the contact member 25), thus short clrcuiting the resistor 43 and causing the full generator voltage to be applied to the field winding 45. As the voltage of the generator builds up to its predetermined normal value, depending on the tension of the spring 32 and the value of resistor 53, the movable winding 5 will be attracted toward the winding 4 against the bias of the spring 32, thus causing the contact members E8 and 24 to separate and introduce the resistor 45 in the field circuit of the generator. The introduction of resistor 46 in the field circuit of the generator causes the voltage or the generator to decrease, thus decreasing the energization of the windings 4 and 5 and permitting the reengagement of the contact members it and 24. The regulator will thus continue to vibrate, causing repeated engagement and separation of the contact members l9 and 24, and a correspondingly increasing and decreasing energization of the field winding 45 within narrow limits to maintain a substantially constant desired voltage on the generator 45.

If the voltage of the generator tends to rise abnormally, or if separation of the contact members l9 and 24 does not occur promptly enough to check the rise in generator voltage, the contact member l9 will be moved away from contact member 24 to engage the contact member 23, thus partially short circuiting the generator field winding 45 and causing a further and more rapid decrease of the generator excitation than is caused by the introduction of the resistor 46 in the generator field winding circuit. In the case of variable speed generators, such as those used on railway cars, the low field excitation demanded at high generator speeds may require that the regulation of the generator voltage will be effected by repeated rapid engagement and separation between contact members l9 and 23 instead of between contact members l9 and 24 as above described. Under this condition of generator operation current impulses pass through resistors 46 and 49, and since this resistor path has negligible inductance, the current builds up and dies out practically instantaneously as the regulator contact members 23 and I9 engage and separate. Since the circuit through the generator armature 42 has appreciable impedance, this abrupt change in current through the regulator contact members produces sharp transient pulses in the generator output voltage. As above stated, these transients tend to shock-excite the various tuned circuits in a cab signal system which receives its power from the regulated generator.

To overcome this undesirable condition, I have substituted a reactor 54, as shown in Fig. 3, for the resistor 49 shown in Fig. 2, and have provided a condenser 55 connected between contact members 23 and IS. A resistor 56 may also be included in series with the condenser 55 between discharge current of the condenser when the contact members 69 and engage.

When the contact members iii and 23 engage, the current through the reactor 5% builds up relatively slowly. Because of this, the transient voltage formerly appearing at the generator termi male is substantially non-existent. 'When the contact members 23 and i9 separate the cur rent flowing through the reactor 5% ceases gradually since it is transferred from the circuit in= eluding contacts 69 and 23 to the circuit including the condenser 55 as limited by the charging of the condenser. This circuit is a series-tuned resonant circuit containing resistance, inductance and capacity. Therefore, when the contact members it and 24 separate, the current oscillates for a few cycles with damped amplitude and finally reduces to zero. Since the impedance of the generator armature circuit is in effect in series with the circuit through the reactor 54, condenser 55, and resistor 45 and this oscillatory current passes through them, a corresponding oscillatory component of voltage appears across the generator terminals. The frequency of oscillations can be predetermined by the proper choice of reactor and condenser sizes, and this frequency selected to be such that it will not interfere with other circuits tuned to other frequencies. For example, the tuned parts of the signaling system can be chosen to be resonant at 100 cycles, and

the tuned circuit here described may be designed to have a frequency well away from 100 cycles.

Modifications in the circuits and apparatus illustrated may be made within the spirit of my invention, and I do not wish to be limited otherwise than by the scope of the appendedclaims.

I claim as my invention:

1. In a regulator system employing an electric generator having a field winding connected in series with a resistor, a contact member connected to the junction between said resistor and field winding and a cooperating contact member for closing a circuit in shunt relation to said field winding, an inductive device connected in said shunt circuit for limiting the rate of current increase upon engagement of said cooperating contact members, and a tuned circuit for discharging the stored energy from said inductive device upon separation of said cooperating contact members.

2. In a regulator for governing the excitation of a generator having a field winding, a. control resistor connected in circuit therewith, a contact member connected to the junction between said resistor and field winding and a cooperating contact member for closing a circuit in shunt relation to said field winding, a reactor connected in said circuit for limiting the rate of current increase upon engagement of said cooperating contact members, and a circuit connection including a capacitor and resistor in series between said reactor and said first named contact member.

3. In a regulator for governing the excitation of a generator having a field winding, a control resistor connected in circuit therewith, means including a pair of cooperating contact members for governing the excitation of said field winding, and means for eliminating undesired transient output generator voltages comprising a tuned circuit controlled by said cooperating contact members.

4. In a regulator for governing the excitation of a generator having a field winding, a control resistor connected in circuit therewith, means ineluding a pair of cooperating contact members for governing the excitation of said field winding, and means for eliminating undesired transient output generator voltages comprising a tuned circuit controlled by said cooperating contact members including a reactor in series with the circuit through said contact members and a condenser and resistor connected in series between said contact members.

5. In a regulator for governing the excitation of a generator having a field winding, a resistor connected in series circuit with said field winding, a pair of cooperating contact members arranged for repeated actuation into and out of engagement with each other for closing and interrupting a circuit in shunt relation to said generator field winding, a damping reactor in said circuit Tor damping the rate of current increase upon engagement of said contact members, and a condenser and resistor in series circuit between said contact members.

DONALD W. EXNER. 

